Abstract
Esterification of palmitic acid was studied on the ammonium salt of 12-tungstophosphoric acid (TPA). The influence of ammonium content of the acid was investigated by preparing partially and fully proton exchanged catalysts. The catalysts were characterised by XRD and FT-IR for their structure and ammonium content, respectively. Potentiometric titration method was employed for the quantification of their acidity. The partially exchanged catalyst, possessing stronger acidic sites, was found to be more active than its fully exchanged analogue.